Provide `NFData1` and `NFData2` instances.

[jonathanknowles]

Related issue:

• Support containers version 0.8. #254

From containers version 0.8 onwards, Map is an instance of NFData1 and NFData2:

-- | @since 0.8
instance NFData k => NFData1 (Map k) where
  liftRnf rnfx = go
    where
    go Tip              = ()
    go (Bin _ kx x l r) = rnf kx `seq` rnfx x `seq` go l `seq` go r

-- | @since 0.8
instance NFData2 Map where
  liftRnf2 rnfkx rnfx = go
    where
    go Tip              = ()
    go (Bin _ kx x l r) = rnfkx kx `seq` rnfx x `seq` go l `seq` go r

Source:

• https://github.com/haskell/containers/blob/7cd38d1e6ab98fdb96bf50496cedb5e0bd2df622/containers/src/Data/Map/Internal.hs#L4600-L4612